Thousands of Lower Mainlanders briefly forgot their New Year’s Day hangovers Thursday by plunging into the frigid waters off English Bay at the city’s 89th annual polar bear swim.

Swimmers — donning everything from hockey gear, clown suits and Batman costumes to thong speedos and party hats —stampeded through the sand and flung themselves into the water, then leapt out screaming.

Seth Brooks, 26, described the plunge as a “sobering experience,” especially given his hangover.